After a couple of days of suspense (well, for anyone closely watching the Oregon Democratic Senate primary), the Democratic Senatorial Campaign Committee finally unwrapped their mysterious advertising effort Thursday.

It turns out that the committee's new ad - which appears to be backed by fairly substantial cash - is an attack on Sen. Gordon Smith, R-Ore. The DSCC has helped one of the Democratic candidates, House Speaker Jeff Merkley, but the new ad avoids taking any position on the D primary being primarily waged by Merkley and Portland lawyer and consultant Steve Novick.

The ad is a fairly standard attack on Smith, accusing him of cozying up to corporate interests and being closely tied to the Bush administration. You could see it as a response to Smith's ad from last week attacking both Novick and Merkley.

One charge in the DSCC ad is rather humorous, though. It cites Smith's vote for a 2005 energy bill that was also supported by 25 Democrats - including Illinois Sen. Barack Obama, who appears increasingly likely to be the party's presidential nominee. And, in fact, the Republican presumptive nominee, Arizona Sen. John McCain, voted against it. So I guess, in this instance, the Democrats are criticizing Smith for being more like Obama and less like McCain.